2014 ML350 OM642 - Low fuel pressure -no start - Add Diesel to tank -Starts!
After the engine quit... code 254000 (Stored) The signal for the pressure sensor of the low-pressure fuel circuit is implausible. Also, code 008700 (Active and Stored) The fuel pressure in the system is too low.
With the live feature of my code reader, low pressure fuel pump in the tank shows only 1.2-1.4 BAR while cranking. HERE IS THE MYSTERY. Pour in a couple of liters of diesel in the tank, ... crank and it starts!
I think the fuel pump, however, worked fine until I did the job. Could it be a faulty pressure sensor somewhere in the front engine compartment? I don't want to drop the tank and replace the pump. (Lots of work and expensive)
What is bizarre is that dumping fuel in tank restores pressure. HELP!



